This is the 36th year of this highly successful research training program in Rheumatology at the Massachusetts General Hospital (MGH), Harvard Medical School (HMS), supported by training grant T32 AR07258. The goal of this program is to train MD, MD/PhD and PhD post-doctoral fellows for independent investigative careers in rheumatology research. Of the 54 graduates of the program that were directly supported by this training grant, many now have faculty appointments in academic medical centers, including holding leadership positions at major institutions as Deans, Scientific Directors, and Division Chiefs. Our program centers on our highly successful clinical fellowship in Rheumatology and our strong basic, translational and clinical science programs situated in an exciting, vibrant and technologically innovative research environment. Our Rheumatology Training Program provides supervised laboratory and clinical research under the guidance of accomplished faculty members, as well as structured training in rheumatology, immunology, clinical trials, biostatistics and ethical issues through courses or conferences. The research focus of the program is the study of the immunopathogenesis of rheumatic disease. Areas of particular interest include autoimmunity, innate immunity, leukocyte trafficking, inflammation, infectious causes of rheumatic diseases, systems immunology, fibrosis, and stem cell biology. Disease areas of particular interest include rheumatoid arthritis, lupus, scleroderma, Lyme, vasculitis and IgG4-related disease. This application requests 4 training positions that will be allocated to trainees who are committed to at least 2 to 3 years of research training. The candidates will be drawn from the MGH Rheumatology fellowship and from post-doctoral trainees already in faculty mentor laboratories. Twelve faculty members primarily from the MGH Rheumatology Unit and its affiliated Center for Immunology & Inflammatory Diseases (CIID) participate in this Rheumatology Training Program and were carefully chosen based on their track record of publication, grants, mentoring, collaboration and a mutual interest in rheumatology and immunology. The training program also leverages many of the research centers at MGH, including the Centers Systems Biology, Cancer, Regenerative Medicine, and Cardiovascular Disease. The MGH provides an outstanding training environment with over 1400 investigators, thematic research centers, trainee support groups, and over $700 million in NIH research grant awards. Opportunities at Harvard University, including course work and the Harvard Clinical and Translational Science Center (a member of the NIH-funded Clinical and Translational Science Award Consortium) and the Broad Institute of MIT and Harvard provide additional valuable resources for trainees. In sum, in this renewal application, we have created a cohesive, integrated, high quality training program in basic, translational and clinical research i the pathogenesis and treatment of rheumatic diseases.